Medicare spent nearly a billion dollars in 2002 on chemotherapy for newly diagnosed elderly breast, colorectal, and lung cancer patients alone, but surprisingly little is known about the extent to which cancer chemotherapies help or harm such patients. This unsettling paradox is the result of the well- described under-enrollment of the elderly on the clinical trials of chemotherapy. In the absence of trials with representative patients, treating oncologists, patients, and policy-makers are left to extrapolate results of clinical trials conducted in younger and comparatively healthier individuals to the general population with cancer, who tend to be older and have greater comorbid disease burdens. Many results of this common extrapolation are unknown. For most cancers, oncologists lack even basic estimates of survival following standard guideline-recommended chemotherapy regimens in elderly patients with cancer. Our broad aim is to compare two standard of care, guideline-recommended, first-line multi-agent chemotherapy regimens (i.e., (1) cisplatin and etoposide (CDDP/VP16) vs. (2) carboplatin and etoposide (carbo/VP16)) in the treatment of ~1,900 elderly Medicare patients with extensive stage small cell lung cancer (ES SCLC) who are drawn from a population-level data source created by the National Cancer Institute (i.e., SEER-Medicare data) according to two outcomes that patients and physicians have affirmatively identified as meaningful. The outcomes are (1) survival time following treatment and (2) invasive hospital-based health care utilization. While CDDP/VP16 has been established through phase III clinical trials as the most efficacious therapy for ES SCLC (i.e., associated with the longest survival), carbo/VP16 has been shown in the same studies to be less toxic and is used more often than CDDP/VP16 for elderly Medicare patients with ES SCLC. Through this work we broaden the lens of comparative effectiveness research (CER) to include outcomes beyond survival alone, outcomes that acknowledge (1) the effectiveness of these treatments in elderly Medicare patients is not yet established and (2) that the avoidance of invasive health care at the end of life may be at least as important to patients as survival time. For example, if CDDP/VP16 and carbo/VP16 are equally effective with respect to survival time following treatment but patients receiving CDDP/VP16 are twice as likely to be admitted to the hospital as patients receiving carbo/VP16, then treatment with carbo/VP16 might arguably be the more effective therapy as it maximizes mortality and minimizes morbidity. This particular information may also be of importance to health policy makers concerned about hospitalizations, the single largest component of Medicare spending for elderly cancer patients. Results of this research will begin to fill what is currently an unacceptable clinical information void in medical oncology regarding the benefits and burdens of national guideline-recommended standard first-line chemotherapy treatments when they are applied to elderly Medicare patients with ES SCLC who are treated in the usual care setting.